hort crops Flashcards
what is in the cucurbitacaea family
cucumbers, watermelon, squash and pumpkin
what are root crop common factors
Deep soil preparation
most are longer-term annuals (over 120 days)
mechandised harvest for commercial growers
postharvest systems specific to each group
give a description of kumara production factors
harvest swollen roots
vegetative parts are frost tender
cuttings are planted
tubers laid for cutting propagation in aug/sept
deep soil preparation is crucial - well-drained sandy loam
harvest the same as potatoes
90%of crop in Dargaville
what is ipomoea batatas
kumara
what is involved with kumara crop health
viruses are a major issue in yeild reduction
pest issues such as Aphids, hawk moth and potato psylid
Diseases: black rot soft rot
give points of potato production establishment
harvest plant tubers
vegetative parts are frost tender
“seed” tubers planted
PH can affect scab incidence
Maincrop planted October - January
what involved with potato crop health
potato viruses major issue - seed certification programme to maintain clean stock
pest issues: potato tuber moth, aphids, potato psyllid
diseases: early blight, powdery scab, late blight
what are the botanical characteristics for onion production
biennial (but grown commercially as an annual unless seed crop
roots very shallow
terminal inflorescence developed after vernalisation; insect-pollinated
bulb harvested - swollen scales, various shapes
industry facts for onion
main exports Uk, Asia
the highest value of vegetable export
Export market quality-focused and there is potential for quality deterioration to occur on the long sea journey to UK
production requirements for onion
seeded in NZ winter- don’t sow too early
tolerant to frost.
weed control is a big issue
dry bulbs production most challenging
early spring and fresh main crop sown apr may
main crop dry bulbs sown august - sept
grown in rotation 1 year in every 3 or 4
Key site factors for onion
good drainage
raised beds
planting material either: seeds, sets, transplants
population density can increase yield but decrease marketable year
pest and diseases for onions
Pests: onion thrips, aphids, onion maggots
disease: botrytis, white rot, downy mildew
post-production - preharvest/ post-harvest - operations onion
leaf condition an indicator of the maturity and general state of the bulb
onions to be stored must mature fully before harvest
when 70-80% of leaves just above the bulb fall over in the whole crop it harvests time
tops and roots cut off by hand or mechanical means
how are onions harested
bulbs lifted from soil to dry
then lifted by hand or machine into bins
aim to minimise the time crop lies on the ground to cure, exposed to the weather,
drying can be done artificially
market criteria for onions
sufficiently dry for the intended use
free from moisture-free from foreign smell or taste
stems twisted or clean cut. no longer than 4 cm
onions must be intact with outer skin included
free from frost damage
problems with storing onions and how to remedy
deterioration in quality due to decay and shooting
reduced by high temp curing and reduced relative humidity storage
onions best stored at 0 degrees and separately to prevent odour transfer
they can last 3 weeks post-harvest or 1-8 months at optimum temperature
cucumber production
harvest fruit of the plant
produce male and female flowers
some varieties are mostly parthenogenic (no polination)
new varieties are mostly gynaecious
vigorous growers, training essential
Harvested relatively immature
cucumber establishment
a strong taproot characterises the root system and may reach 1 meter deep
the root system is extensive but rather shallow
growth is in two stages 1. upright growth until 5-6 nodes stage 2. vining, side shoots begin to emerge while the main leader continues to grow. plant flops over. each flower/fruit is borne on its own stem attached to the main stem
describe the flower and fruits of cucumbers
different flower types male, female, hermaphrodite
flowers require pollination via bees
some plants only produce female flowers and need a pollinizer but are very productive
how does pollination work for cucumbers
each cucumber flower is open only one day.
10-20 visits per flower is needed
bees should be brought in at 20% flower burst
not to early or too late
pollination in gynoecious female flowercrops are blended with monoecious seed at a ratio of 88%- 12%
requirements for growth of cucumbers
high temperature, humidity, and light intensity and with an uninterrupted supply of nutrients.
need frequent pruning of main stem and laterals.
too much fruit can result in the plant being exhausted, abort fruit
cucumbers are sensitive to unfavourable conditions and slight stress affects their growth and production
air temp is the main environmental component larger the variation the better 19-20 night 20-22 day temp
cucumber health problems
damping-off of seedlings
black root rot
powdery mildew
fruit: scab, botrytis
lettuce production requirements
nutrient demand high especially nitrogen
key plant health issues with lettuce aphid ( biggest problem), big vein disease in cool climates
warm soils
free draining
usually transplants
